In a power semiconductor module such as a power conversion module, as the speed of a switching operation is increased, occurrence of element breakdown and noise due to an overvoltage in turnoff operation becomes problem. The overvoltage in turnoff operation is proportional to inductance and the time rate of change of the current flowing in the power semiconductor module (di/dt).
If a long switching time is taken in order to suppress the overvoltage, the switching operation becomes slow. At the same time, the switching loss expressed by the time integration of the products of currents and voltages is increased. In order to suppress the overvoltage and reduce the switching loss, it is desired to reduce the inductance of the power semiconductor module.